Acrylonitriles and substituted acrylonitriles as fumigants



Patented Aug. 1944 OFFICE ACRYLONITRILES AND SUBSTITUTED. AoaYLoNITarLEs AS FUMIGANTS Vartkes Migrdichian, Greenwich, Conn assignor to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application December 9, 1939. Serial No. 308,389

7 Claims.

This invention relates to pest control agents and more particularly to those belonging to a class 'of compounds adapted to the fumigation of enclosed spaces for the eradication of insects and allied pests and to methods of fumigation therewith.

I have discovered that valuable pest control properties are exhibited by the group of organic chemical compounds having the followin structural formula:

in which R, R and R represent hydrogen, an aliphatic hydrocarbon radical or a halogen substituted aliphatic hydrocarbon radical. This group of chemical compounds includes a large number of substances of which the following are typical: acrylonitrile, fi-methylacrylonitrile, 13,,9-

dimethylacrylonitrile, fi-ethylacrylonitrile, ,B-isopropylacrylonitrile, fi-isobutylacrylonitrile,

methylacrylonitrile, a-ethylacrylonitrile, a-chlo'romethylacrylonitrile, and m-bromomethylacrylonitrile.

Acrylonitrile is particularly suited to pest control by fumigation methods as it has a high vapor insecticides.

Where used as fumigants, the compound either alone or in admixture with others is applied, for example, as by atomizing or vaporizing with or without heat into the enclosure a-measured quantity of the material either at atmospheric pres- These comsure or at reduced air pressures, pounds may also be introduced into the space to be fumigated in the form of impregnated solids such as kieselguhr or cellulosic board or other absorbent bodies carrying the compounds. They may also be used in the form of solutions or emulsions, from which they are subsequently vaporized. When used as contact insecticides, they may be sprayed directly on the life to be killed The invention will be illustrated in greater detail by the fumigation tests performed on various insects, listed in the following table:

Dosage Expos Per Insect Fumigant oz./l000 ure cent cu. feet hours kill Flour beetle Acrylonitrile 4 4 98 Do. do v 5 4 100 Rice weevil l 4 D0 2 4 100 Tobacco beetle. 2 4 88 0 3 4 100 Cockroach l 4 100 Carpet beetle. 6 4 60 D04. 8 4 100 Apliis rumicis.' 10 16 100 Citrus rcd spider. l0 1 87 Do..." l0 16 100 Resistant Calif. '10 l red scale.

D0 10 '16 Citrus mealy bug l0 16 Southern army 10 16 100 worm. Rice weevil a-Methylacrylomtnle. 8 4 84 o 12 g Eth lacr lom'trile... 12 do 24 4 94 d0 20 4 91 do 2g 2 182 -Eth lac lo f- .d( l2 4 100 a-Chlorometliylac- 0.5 4 100 rylonitrlle. Flour beetle ..do 1 4 11 Do do 2 4 I 100 Among these useful compounds acrylonitrile, as a typical example, presents numerous advantages in the fumigation field as compared to known fumigants. It possesses insecticidal power to a high degree and is sufliciently volatile to establish the proper concentration under the condltions encountered. It is non-corrosive and does not develop high pressure in the container under usual conditions, hence it may be stored and shipped in ordinary vessels. It does not possess an objectionable odor and will not leave an undesirable odor in goods fumigated therewith. It has alower rate of toxicity for man and warm blooded animals as compared with hydrocyanlc ness of acrylonitriie as against other typical tumigants:

Minimum lethal dose for 4-hr. exposure oz./l, cu.ieet

Fumigaut Confused Rim weevil flour beetle Aerylonitrlle 2 5 4 Chlorpicrin 4 8 In utilizing the fumigants of this invention, it is possible to avoid protective stupefaction). a characteristic which is encountered when insects, of which the active rice weevil is typical, are exposed to hydrocyanic acid gas. Sorption experiments have shown that insects of this type take up considerable quantities of hydrocyanic acid gas during the first one ortwo minutes of exposure,

I space to be iumigated.

' 5. A method of fumigating insects which comand thereafter become stupefied with a result that the gas is sorbed at a very low rate and the kill in many instances is by no means satisfactory. This protective characteristic has been explained by assuming that the first rapid uptake of hydrocyanic acid gas by the active insect occurs in the tracheal tubes, and that after the insect becomes stupefied, the fumi'gant is prevented a from entering these tubes by means of a closing mechanism. 1'

These compounds may be used alone or in admixture with other fumigants, insecticides or diluents, or with compounds which render the liquid or the vapors given of! from the liquid non-inflammable and thus completely eliminate the fire hazard.

While the invention has been described with specific reference to particular embodiments, it

is to be understood that it is not to be limited thereto, but is to be construed broadly and restricted solely by the scope oi. the appended claims.

consisting of hydrogen, an aliphatic hydrocarbon radical of less than five carbon atoms and a halogen substituted aliphatic hydrocarbon radical of less than five carbon atoms.-

3. A method of Iumigating insects which comprises vaporizingacrylonitrile into the space to be Iumig'ated.

4. A method of fumigating insects which comprises vaporizing p-ethyl acrylonitrile into the prises vaporizing a-chloromethyl acrylonitrile into the space to be fumigated.

6. A method of fumlgatin'g insects which includes establishing in the space tobe fumigated a concentration of acrylonitrile in' substantially the proportion of at least one ounce per 1000 cubic feet.

7. A method-of controlling insects which inl cludes the step of exposing the same to a toxic amount of a compound having the formula:

in which R R and R. are chosen from the group consisting of hydrogen, an aliphatic hydrocar- 'bon radical and a halogen substituted aliphatic hydrocarbon radical.

VARTKES MIGRDICHIAN. 

